Contact with energized electrical circuits and equipment is widely recognized as a serious workplace hazard that can lead to serious injuries and even death by electrocution or other deleterious secondary effects, such as trauma after a fall. In some instances, the hazard is immediate and apparent, but in others, the danger may be indirect. For example, there is an immediate and recognizable hazard for electricians or other workers who deliberately come into direct contact with actual electrical equipment while installing or repairing it. In theory, the hazard can be removed by de-energizing the equipment, but unrecognized faults or human error all too often cause a worker to believe the work can safely proceed, even though there is still a shock hazard. In some situations involving high voltage, mere proximity without actual contact may be sufficient for the worker to experience injurious shock or even electrocution. In addition, workers can inadvertently come into direct contact with energized circuitry or be exposed as the result of indirect contact by cranes, forklifts, ladders, or other like workplace equipment or tools through which current is conducted to the user.
Although high voltages are often perceived as more dangerous, a sustained electric shock from an ordinary 120 V/60 Hz source can easily result in ventricular fibrillation, since the shock intensity may exceed the let-go threshold, while not delivering enough initial energy to propel the victim away from the source.
Protection is sometimes provided in the form of non-contact detectors or testers that are capable of sensing harmful voltages before and during the activity of a worker. Often, these detectors are constructed in a pen-like housing to make them easy to carry and use. In situations when high voltage is expected, a suitable detector is sometimes mounted on a long, non-conducting pole to permit the worker to manipulate the detector into the desired detection region while maintaining a safe distance. However, in either of these situations, the testing is typically done once at the beginning or at irregular times during the course of a job that are not correlated with the worker's continuing activity. Such testing, carried out prior to a worker's entry into an area or the initiation of a given job activity, can often avert danger. Nevertheless, a hazard could arise later and without the worker being notified. In a complex job site, the activities of other workers could conceivably energize circuitry without knowledge of the entire workforce, so that activity that had been cleared by preparatory testing might later become dangerous.
A voltage detection system that operates continuously and without the need for specific action or interruption of a worker's routine would afford protection against such circumstances. A system integrated with other conventionally used personal protective equipment, would be especially useful and convenient in enhancing worker protection.